Drill bits



Nov.,. 26, '1957 w. e. GREEN 2,

DRILL BITS Original Filed Sept. 26, 1947 2 Sheqts-Sheet l 72 "7 37 73 INVENTOR $5, WILLIAM G. GREEN J AQ O Mp.

Nov. 26, 1957 w. G. GREEN 2,814,465

. DRILL BITS Original Filed Sept. 26, 1947 2 Sheets-Sheet 2 INVENTOR WILLIAM G, GREEN AGENT United States Patent 6) DRILL BITS William G. Greeng. Garland; hexassi'guor, by mesne assignments, to A. D. Applebyrfldessa, Tex.

Original application September 26, 1947, Serial No. 776,314,, new Patent No; 216545577; dated October 6', 1953. Divided and thisrapplication May 4', 1953; Serial No. 3525864 4 Claims. ((315.255-341).

This invention relates to drill bitsand' more particularly to deep well bits of the type which include a plurality of rotatable cone cutters mounted-on the bit head.

In the artof deep well drilling it is customary to'rotate in the borehole a hollow drill bi'thavinga head portion provided with forks in each-ofwhich is'rnounted a'spindle for supporting; for free rotation; a cutter con'e having serrated faces for cutting or abrading the ground orrock in which the" well is being dr-illediv Mud is supplied cen= trally to the drill bit andis discharged overthe cutters to wash away the cuttings and to lubricate the exterior of the cutters. In viewof the great weight which is tra'nsrnitted to the cutters through their respective spindles; a bearing problem: of considerable magnitude is presented: In attempts to solve this problem resort has been had to various bearing arrangements. While some of the'bearing arrangements involve anti=friction= elements which render the cutters more freely rotatable, the resistance of these to heavy shock has not been heretofore entirely satisfactory, with the result that frequent andc'ostly'replacements of the cutter cone assemblies have beennee essary.

Another problem related to the bearing stru'ct'ure isthat of lubricating the bearing surfaces between the'cutt'e'n and spindle. These are customarily lubricated during assembly and are not susceptible of subsequent lubrication: without disassembl'y. Thus it may be that some of the bearing failures heretofore frequently' encountered were due to failure of lubrication.

It is an object ofthe present invention to: provide a drill bithaving a cutter and spindle assembly which is characterized by case of assembly and installation; great mechanical strength; adequate turning. freedom: on the part of the cutter, very high resistance to shock and high resistance to bearingfailure.

It' is contemplated, according t'o' the'prese'nt" invention, to provide an improved cutter assembly'which is suscep* tible of easy lubrication without disassembly'antlwhich may be lubricated during use.

The primary object of this-invention, which is a division of copending application No; 776,314; filedl'September 26, 1947, now Patent No. 2,654,577, granted October 6,1953, is to provide a drill'bit of the type described which includes a novel means of assembly between the'spindle and spindle head.

Other objects and advantages ofthe invention willbe apparent upon consideration of'the following detailed. description of several embodiments thereof in conjunction with thev annexed drawings wherein:

Fig.. 1 is a fragmentary view in vertical sectionof a drill. bit and.cutter cone assembly of this.invention'..

Fig. 2 is a view in verticalsection illustratinga step in the assembly of the apparatus ofFig. 1.

Fig. 3 is a sectional view taken along the lines 3-3 of Fig. 1.

Fig. 4 is a detail view of the compressible ring employed as an auxiliary bearing means in the drill bit of this invention.

Fig. 5 representsra viewinisection corresponding-to the line 5--5' in Fig; 1;

Fig. 6 is a fragmentary sectional elevational view of another embodiment of this invention.

Referring now more'particularly to the characters of referenceon the drawing, in Fig. 1, a drill bit assembly employing the invention at hand is representedby numeral 51. This assembly isseento consist basically of a tapered threaded shanlportion- 11 adapted for attachment to the mud pipe of the drillr-i'g andthree' forks 12', supporting cutter cone assemblies 133 The forks 12" are provided respectively with tines'12a'ancl I'2b, defining between them a space for the reception of wedge-shapedspindle lip 70. The bit head is' hollow and i'sprovided with a mud channel 16, a manifold 19, mud dischargeconduits 18-, for serving the several' cutter co'u'e assemblies to be mounted onthe drillhea'd.

The cutter cone assembly 13 illustrated in Figures 1 and 5 is comprised of a catter cone 71 provided with cutter teeth 72and' 73 arranged in' rows about the outer surface. The exterior surface of the. cutter cone and teeth thereof are conventionali The interior of cutter cone 71 has cylindrical wall 74 terminating in a frusto-conical surface 75. The cutter cone is supported from a bearingassembly comprising a portion of the spindle head 59 and spindle 60.. The parts 59 and. 60' are joined: by a novel means as will best be seen by reference. to Figs. 2 and3. A. sleeve 63 on spindle head 59 extends. in an annular recess or opening 83 between the spindle proper and a central, generally cylindricalcore member 64 attached thereto, or integral therewith. The corev 64. is provided witha series of; spaced. radial projections. 65 disposed. in an annular path about itsv outer surface. The surfaces of the members 65 arecurved. and a complementary curved groove, 66 is cut in the spindle 60. The circumferential spacing. of the projections. 65 allows for the distortion of the sleeve 63 whichis,indicateddnFigure 3. Itis now apparent thatwhen the spindle 60 is. to be. attached to spindle head 59, it isonly. necessarythat. the two be ham,- rnered together in the direction of the arrow. indicated in Fig. 2 to cause the sleeve 63 to be distorted in its passage around the'spaced members 65'of the, core 64. This effects a. relatively permanent locking of. the core member 64 to the wedge member-.whilethelocking of the cutter cone.71..against:axiahmovementrelative to the. supportingassembly is efiected as in. Fig- 1. by the use. ofxa dual'ring assembly in a recess. designated in the drawings at. 67 whichziscornprised oftwo rings 37. Each ring: 37 is split at: 39, as shown in Fig. 4, to facilitate it's insertion into the annularrecess 67 withinthecutter cone 71. Each ring- 37 also may be providedon its. outer surface with a groove or channel 40 which serves as an oil retention groove and further torprevent thetoo-rapid migration of the. oil fromthe end of the'channel 14=to-the packing rings 68 and 69. The oil distribution grooves14- and packingsare alsoshown-in Fig. 1-.

It'wilkbenotedthat'the sealing gaskets 68 and 69areso located that the thrust. incident to: the rotation of the cutter conetends to compress them to-improvetheireificacy' in: preventing outleakage' of l'ubricanti Lubrication of the" bearing. surfaces 74 and 75' is: ac:- complislied-by'the arrangement shown in'Fig 1 Within the bottom portion: of the: drill bit? assembly 51" there: is provided a pressure accumulator'52' comprising a. storage tank. divided intotwo workingspacesby a'piston': 532 The piston'is urged'downwardly'by a spring54 and is moved upwardly. by: liquid" ins the Working: space: 55- which: com:- municates through a passageway 56 in the drill head and spindle head with a passageway 57 extending from a lubrication fitting 58 through the spindle head 59 and the spindle 60. The working space 61 having therein the Patented Nov. 26, 1957 spring 54 of the pressure accumulator 52, is provided with an air vent at 62. It can now be seen that when lubricant is provided under pressure at fitting 58, not only will it be pumped through the passageway .to the bearing between the cutter cone and spindle and spindle head, but it will also be forced upwardly through the passageway 56 to the working space 55, causing the piston 53 to move upwardly against the thrust of spring 54 until the space 55 is completely filled with the lubricant. Thereafter when the drill is put into use, it is apparent that as the lub icant works out from underneath the cutter cone, an additional supply is rendered available by the stored energy in the spring 54 which will pump lubricant from the space 55 through the passageways 56 and 57 into the bearing space between the cutter cone and its supporting structure.

Referring now to Fig. 6, there is shown a modified form of a drill bit unit of this invention involving a cutter cone 41, a spindle 42, a spindle head 43, and ball bearings 4-4. The cutter cone 41 corresponds generally in configuration to the cutter 71 except that instead of having a groove such as the groove 67 therein, it has an arcuate groove 45 defining a portion of a ball race. Complementary portions of the ball race are formed in the spindle 42 and in the spindle head 43, and the resulting ball race accommodates the balls 44 about which the cutter cone 41 can rotate and prevent axial displacement of the cutter head during operation. The attachment of the spindle head 43 to drill head 51 corresponds to that shown for spindle head 59 in Fig. 1. Packing rings 46 and 47 are provided to prevent the escape of lubricant. The core 80 of spindle 42 is provided with a central passageway at 48 having a grease fitting 49 and an open end at 50 discharging into the bearing space between the cutter cone and the spindle. The assembly of the embodiment of Fig. 6 is similar to that shown in Fig. 1 except that projecting threads 81 on spindle head 43 engage internal threads 82 of spindle 42 in lieu of the projecting sleeve 63 engaging the opening 83 in spindle 60. Additionally balls 44 are inserted in the ball race defined by groove 45 and cojoining grooves 84 and 85 in the spindle and spindle head respectively. The embodiment shown in Fig. 6 also differs from the embodiment of Fig. 1 in the absence of the lubricant pressure accumulator 52, and associated parts. Helical groove 32 provides for the distribution and retention of lubricant within the conical section of the cutter cone, and through the ball grooves 45, 84. and 85. A screw driver slot 28 in the end of core 80 permits assembly or disassembly of the drill bit unit.

From the foregoing description it will be readily seen that there has been produced a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of this invention, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention as defined in the appended claims.

Having thus described the invention, what is claimed as new and useful and is desired to be secured by Letters Patent is:

1. A drill bit comprising a head portion, a fork extending from said portion, a spindle head secured to said fork, a spindle, said spindle and spindle head having respectively complementary core and sleeve members for connecting said spindle and spindle head together, said sleeve member being telescoped in the spindle around at least a portion of the core, said spindle head and spindle defining a large bearing surface interrupted by a groove, a cutter having a bearing surface complementary to that of the spindle and spindle head and a groove registering with the groove of the spindle and spindle head, said cutter being mounted for rotation on the spindle and spindle head, and

annular means lying in said grooves to absorb the axial thrust of the cutter, said core being provided with a radially enlarged circumferentially interrupted projection, said sleeve being deformable to permit distortion of said cylinder in passing over said core, whereby a permanent grip between the spindle head and spindle is effected by pressing them together.

2. A drill bit comprising a head portion, a fork extending from said portion, a spindle head secured to said fork, a spindle. said spindle head having an integral axially projecting sleeve thereon having a relatively thin annular wall of deformable material, said spindle having a cylindrical recess therein in matching alignment with said spin dle head sleeve, a cylindrical core attached to said spindle and occupying said recess, said core including spaced radial projections on its circumference, said spindle including a curved groove complementary to but spaced from said projections, said core and projections defining an annular recess with said spindle and curved groove, said spindle adapted to be firmly attached to said spindle head by forcing said annular wall into engagement with said radial projections and thereby deforming said annular wall around said spaced projections and into said curved groove; said spindle head and spindle defining a large bearing surface interrupted by a groove, a cutter having a. bearing surface complementary to that of the spindle and spindle head and a groove registering with the groove of the spindle and spindle head, said cutter being mounted for rotation on the spindle and spindle head, and annular means lying in said grooves to absorb the axial thrust of the cutter and provide additional bearing means for said cutter cone.

3. A drill bit comprising a head portion, a spindle head carried by the head portion, a sleeve member extending axially from one end of the spindle head, a spindle surrounding the sleeve member and separate therefrom, a core member extending from the spindle and telescopcd in the sleeve member, means forming an annular groove in one of said sleeve and core members and a rib on the other of said sleeve and core members interfitting in the groove and securing said members against relative axial movement, and a cutter surrounding the spindle and spindle head and journaled relative thereto.

4. In a drill bit, a head portion having a spindle head thereon, said spindle head having a sleeve portion extending from an end thereof, a spindle surrounding the sleeve. a core member extending from the spindle in the sleeve, a cutter surrounding the spindle and spindle head and journaled relative thereto, said cutter and spindle having a lubricant passage therebetween, and means for supplying lubricant to said passage including a passageway through the core member axially of the spindle to the end thereof remote from the spindle head, and a device connected with said means for supplying lubricant to said passageway.

References Cited in the file of this patent UNITED STATES PATENTS Re.l5,194 Patin Sept. 13, 1921 930,759 Hughes Aug. 10, 1909 959,539 Hughes May 31, 1910 1,238,757 Gardner Sept. 4, 1917 1,305,489 Patin June 3, 1919 1,649,858 Reed Nov. 22, 1927 1,909,128 Scott et al May 16, 1933 2,009,300 Reed July 23, 1935 2,065,742 Reed Dec. 29, 1936 2,076,002 Reed Apr. 6, 1937 2,513,634 Francis -s July 4, 1950 

